Various methods for applying markings to roadway and walkway surfaces are known in the prior art. For example, it is well-known in the prior art to apply colored thermoplastic markings to asphalt roadways, such as traffic arrows or lane markings. The markings are fixed in place using heat which causes the settable material to bind to the underlying substrate.
It is also becoming increasingly common to apply surface markings to outdoor substrates for decorative or marketing purposes. For example, corporate logos and advertising designs may be applied to asphalt, concrete or other substrates, such as in parking lots, drive-throughs, store fronts and the like.
Thermoplastic surface markings are typically heated in situ by using hand-held open-flame torches. However, it is very difficult to consistently apply heat to surface markings using such hand-held heaters, particular if the markings are large in size. As a result, two primary problems have arisen, namely overheating and underheating. Often the thermoplastic material is either scorched due to the application of excessive heat or fails to bond consistently to the underlying substrate due to the application of insufficient heat. The failure to establish a consistent bond may result in delamination of the marking from the substrate over time, especially in high traffic areas.
The need has therefore arisen for an improved method and apparatus for gradually and consistently applying heat to surface markings to ensure a consistent bond with the underlying substrate, even in the case of markings having a very large surface area.